Circuit breaker



Sept. 7, 1943.

F. B. ADAM EIAL 2,328,767

CIRCUIT BREAKER Filed July 31. 1940. 5 Sheets-Sheet 1 3! B/me'f'a/ x 223" filme-fal Q 9- 3 L j Elms-fa] Wl ENTORS 42 HENRY M. ST/EGL/TZ 36 BYFREDERICK 15. ADAM Sept. 7, 1943. F. B. ADAM ETAL 2,328,767 CIRCUITBREAKER I Filed July 31, 1,940 5 Sheets-Sheet 2 Sept. 7, 1943. F. B.ADAM ETAL 2,323,767

CIRCUIT BREAKER Filed July 31, 1940 5 Sheets-Sheet 5 57 2O TIP/9J2.

Hey/5:

HENRY /\/l. S 77561. ITZ FREDERICK B. ADAM 7ZA%Y.

Sept. 7, 1943.

F. B. ADAM EI'AL CIRCUIT BREAKER Filed July 31, 1940 5 sheets-sheet 4WVENTORS:

HENRY M. ST/EGL/TZ REDERlCK BQADAM F, AL,

' CIRCUIT BREAKER 5 sheets sneet 5 Filed July 31, 1940 f WW I WVE/V TORSHENRY M 577EGL/TZ FREDERICK B. A DA M Patented Sept. 7, 1943 CIRCUITBREAKER Frederick B. Adam, St. Louis County, and Henry M. Stieglitz, St.Louis, Mo.

Application July 31, 1940, Serial No. 348,776

19 Claims.

This invention relates to improvements in switches and automatic circuitbreakers. More particularly, the invention relates to improvements insmall enclosed type switches and automatic circuit breakers that areoperated by rotatable actuating means.

It is one object of the invention to provide an improved enclosed typeswitch or circuit breaker.

In many of the switches and circuit breakers now in use, snap action ofthe movable contact is obtained by the employment of complicated systemsof springs and levers. Such switches and circuit breakers areobjectionable because the use of complicated systems of springs andlevers makes the devices expensive. The present invention avoids theobjection outlined above by providing snap action for the movablecontact without using a complicated system of springs and levers. It is,therefore, an object of the invention to provide a simple snap-actingmechanism for switches and circuit breakers of the enclosed type. 1

Difiiculty has been encountered in maintaining adequate contact pressurebetween the contacts of small enclosed type switches and circuitbreakers. In some of these devices, contact pressure is secured by thebendin of the contacts. Such construction is not entirely satisfactorybecause materials of which contacts are ordinarily made do not have muchresiliency. The invention avoids this objection by providing means tomaintain intimate engagement between the contacts which is independentof the resiliency of the contacts. It is, therefore, an object of theinvention to provide a switch or circuit breaker of the enclosed typewherein contact pressure is secured by means that is not dependent .onresiliency of the contact.

In some of the small enclosed type circuit breakers now in use,difficulty has been experienced in preparing them for circuit-closingoperation after they have been tripped by an excessive current, Theinvention provide means to automatically return the actuationg means ofthe switch or circuit breaker to the o r position on the occurrence ofan overload, and it is, therefore, an object of the present invention toprovide an automatic circuit breaker of the enclosed type whichautomatically prepares itself for circuit-closing operation after thebreaker has been tripped.

When the circuit is broken by some of the circuit breakers and switchesnow in use, burning occurs on the copper on which the contact issupported. Such burning shortens the life of the device and is,therefore, quite objectionable. The invention obviates the objectionoutlined above by providing means to prevent the burning of the coppercontact support and restrict any are that might form to the surface ofthe arc-resisting contact. It is, therefore, an object of the presentinvention to provide a contact support and a coating therefor thatlimits any are which might form to the surface of the contact.

Where automatic circuit breakersusing electrothermally responsive meansto open the circuitin response to an overload current are exposed toheat, the circuit may be broken by a current that is less. than thecurrent for which the device is rated. Such circuit breakers are notdependable since they permit interruptions of service that are notnecessary. The invention obviates any such interruption by providingmeans to compensate automatically for the efiect of ambient temperatureon the circuit breaker. Such an arrangement permits the circuit breakerto operate only when an overload current of greater strength than therated current occurs. It is, therefore, an object of the presentinvention to provide an automatic circuit breaker having means tocompensate for ambient temperature.

It is often desirable to use several small automatic circuit breakers ofthe enclosed type independently of the actuating means to show whetheror not the circuit is closed. It is, therefore, an object of the presentinvention to provide a small automatic circuit breaker of the enclosedtype having means that operates independently of the actuating means toindicate whether or not the circuit is closed.

Other objects and advantages of the invention will be shown anddescribed in the drawings and accompanying description.

Several preferred forms of the invention are shown and described in thedrawings and accompanying description, but it is to be understood thatthe drawings and accompanying description do not limit the invention andthat the invention 7 will be defined by the appended claims.

In the accompanying drawings, Fig. 1 is a cross-sectional View of theinvention as applied to a circuit breaker, and shows the elements of thecircuit breaker in the on position.

Fig. 2 is a cross-sectional view of the elements of the circuit breakerin the ofl'position.

Fig. 3 is a. cross-sectional view of the elements of the circuit breakerin the off position after the circuit has been broken in response to anoverload current condition.

. Fig. 4 is a cross-sectional view of the elements of a switch of thesimple, non-automatic type to which the invention may be applied. Theelements are shown in the on? position.

Fig. 5 is a perspective view of a terminal'used in the circuit breakerand switch.

Fi 6 is a cross-sectional view of the switch shown in Fig. 4, that istaken along the plane Sa, and shows an end view of the switch.

Fig. 'I is a cross sectional view of the insulating housing of theswitch taken along 7-7 in Fig. 4.

Fig. 8 is a view of the bottom of the casing in which the circuitbreaker or switch may be mounted.

Fig. 9 is a cross-sectional view of an optional form of the inventionand shows the elements of the device in the on position.

Fig. 10 is a partial cross-sectional view of the optional form of theinvention of Fig. 9 immediately after the circuit has been broken inresponse to an overload current condition.

Fig. 11 is a side elevational view of the actuating means used with theinvention.

Fig. 12 is an end elevational view of the actuating means shown in Fig.10.

Fig. 13 is a perspective view of the actuating means shown in Figs. 11and 12.

Fig. 14 is a perspective view of one preferred form of semi-fixedcontact support used in the invention.

Fig. 15 is a plan view of a magnetic choke shown in position in Fig. 25and Figs. 1, 2 and 3.

Fig. 16 is an end elevational view of the magnetic choke shown in Fig.15.

Fig. 17 i a side elevational view of one form of spring that biasestheactuating means to theoff position.

Fig. 18 is a perspective view of the spring shown in Fig. 17.

Fig. 19 is a side elevational view of the contact carrier used in thepreferred form of circuit breaker.

Fig. 20 is an end elevational view of the contact carrier shown in Fig.19.'

Fig. 21 is a bottom view of the contact carrier shown in Fig. 19.

Fig. 22 is a view of the spring which assures intimate contact betweenthe movable and fixed contact in the circuit breaker and switch.

Fig. 23 is a view of an insulating member that acts as a baffle plate inthe bottom of the casing that encloses the circuit breaker.

Fig. 24 is a perspective view of the contact carrier used in thepreferred form of circuit breaker.

Fig. 25 is a view of an optional form of semifixed contact support. I

Fig. 26 is a cross-sectional view of another optional form of theinvention showing the elements of the device in the on position.

Fig. 27 is a side elevational View of the semifixed contact support usedin the device shown in Fig. 26. i

Fig. 28 is a plan view of semi-fixed contact shown in Fig. 27. I

Fig. 29 is a view of an optional form or spring that biases theactuating'means to the "011 position.

Fig. 30 is a view of an optional form of electroresponsive means used inthe device shown in Fig. 26.

Fig. 31 is a view of the transverse bar used in the invention.

Fig. 32 is a cross-sectional view of an automatic circuit breaker of theenclosed type having means to compensate for the effect of ambienttemperature.

Fig. 33 is a perspective view of an indicator that acts independently ofthe actuating means to indicate whether or not the circuit is closed.

Fig. 34 is a side view of a spring that is used with the indicator shownin Fig. 33.

Fig. 35 is an enlarged perspective view of the means that compensatesfor ambient temperature, and

Fig. 36 is a perspective view of a modified form of transverse bar usedin the invention.

Referring to the drawings in detail, Figs. 1, 2,

a and 3 show three positions of the elements of a preferred form of theinvention. The elements of this form of the invention are positioned ina casing or housing 22. This casing is preferably made of moldedinsulating material and has formed portions that guide and support theelements of the device. Anactuating means 20 is positioned in a recessin the housing and rotates about the axis of a projection thereon, whichengages a socket in the casing. As shown in Figs. 11, 12, and 13 theactuating means 20 has a recess 2| therein and a. raised portion IS onthe periphery of the actuating means adjacent the recess. The recess 2|in the actuating means is designed to receive a cam portion 25 on atransverse bar 26. This bar is rotatably secured-to contact carrier 28and is normally held at one end by electro-responsive'means 32 and heldat the other end by actuating means 20. In the preferred form of theinventionshown, the electro-responsive means is a bimetallic strip, butany means that operates in response to an overload current condition maybe used. The recess 2| in the actuating means 20 also receives one endof spring 24 which is supported by the casing 22. Attached to thebimetal 32 is a flexible conductor 34 that connects terminal 40 withwith the electro-responsive means 32. The terminal 40 shown in Fig. 5 isdesigned to be secured to casing 22 without a positive connectiontherebetween. The electro-responsive means 32 has a contact 56 mountedon one end thereof and a stop 3 mounted on the other end thereof. Thestop 3| on one end of the electro-responsive means 32 normallyengagesand holds one end of the transverse bar 26. The other end of the bimetaland the contact 56 thereon, engage and are held by the contact carrier28. 'I'he'contact carrier 28 as shown in. Figs. 19, 20, 21 and 24comprises two sections of insulating material that are held together bya suitable means. The contact carrier has recesses in which theelectroresponsive means 32 is held, and has projections on the sidesthereof that engage formed portions of the casing and guide the movementof the concontact support 38. The contact support 38 is designed toengage formed portions of the casing and be supported and restrainedthereby. The contact 44 is biased toward closed circuit position by theaction of a spring 36 that is positioned in the bottom ofthe casing.This spring 36 presses contact support 38 upwardly against formedsections of the casing 22 when the circuit is open, and presses thecontact 44 against contact 56 when the circuit is closed. An opening 43is provided in the bottom of the casing 22 to permit any gases generatedby electrical arcs to escape from the casing. A baflle plate 42 oi.insulating material may be positioned in the bottom of the casingadjacent the opening 43 and may be loosely supported by formed portionsof said casing.

To operate the device shown in Figs. 1, 2, and 3, so as to close thecircuit, the actuating means 26 is rotated in a clockwise direction tothe on position. The rotation of actuating means 20 is resisted by thecombined force of springs 24 and 30, As the actuating means 20 rotates,its end slides along, the cam profile 25 formed on transverse bar 26 andexerts a downward acting force on the cam end of the bar. Since themiddle of the bar is pinned to the contact carrier 28 and the other endof the bar 26 isv held by electro-responsive means 32, the downwardforce on the cam end of the bar causes the downward movement of thebarand the contact carrier. As the actuating means 20 continues torotate, the edge of the recess 2| therein engages a raised portion 21 onthe cam portion 25 of bar 26 and thus obstructs easy operation of theparts to the full closed position. This obstruction necessitates theapplication of additional force to continue the rotation of theactuating means 20 to the full closed position. The raised portion 21 ispositioned near the upper limit of the cam profile 25 so that the forcerequired to rotate the actuating means past the raised portion 2'! willbe more than sufficient to rotate the actuating means into the full onposition. This arrangement insures that the impulse applied to theactuating means immediately ahead of the position where the contactsengage will be sufilcient- 1y great to move the contact carrier intofull on position once the obstruction to easy operation is passed. Themovement of the contact carrier into the "on position results in theengagement of contacts 56 and 44 and the bending of semi-fixed contactsupport 38. The bending of the contact support 38 is resisted by thespring 36 that is positioned beneath the contact support 38. Thepressure exerted by the spring 36 insures intimate contact betweencontacts 44 and 56.

To open the circuit, the actuating means 28 is rotated in acounter-clockwise direction. As the actuating means is rotated, raisedportion IS on its periphery engages the profile of the cam portion 25 ofthe transverse bar 26. This engagement between the raised portion l9v onthe actuating means and the cam profile 25 of the bar 26 obstructs easyoperation of the parts immediately ahead of the position where thecontacts 44 and 56 separate to break the circuit and, hence, a greaterforce is required to move the parts past this position than is requiredto move the handle 20 through the remainder of its orbit. Consequently,the impulse required to overcome the obstruction to easy operation thusprovided is such that when the obstruction is passed the parts movequickly to the extreme positions. This I quick action of the actuatingmeans permits the contact carrier to move quickly into the ofi" positionunder the biasing force of the spring 30 and prevents the holding of anare between con- 5 tacts 44 and 5S.

Whenever an overload current condition occurs when the switch is closed,the bimetal 32 gets warm and bends outwardly. The outward bending of thebimetal causes stop 3| to move out of engagement with the end of bar 26.This movement of stop 3| permits contact carrier 28 to move upward andpermits bar 26 to rotate under the biasing force of spring 36, Thesudden release of bar 26 by the movement of stop 3| 5 disturbs theengagement between actuating means and the cam portion of bar 26. Thisdisturbance permits actuating means 20 to rotate to the oif positionunder the influence of spring 24 and permits contact carrier 28 to 20move to the full off position. As the bar 26 is carried upwards by thecontact carrier 28, it contacts a projection 80 that is formed on thecasing 22. This projection is so positioned that the end of bar 26 isheld below the lower edge 5 of stop 3| on bimetal 32 when the contactcarrier 28 is in the off position. The maintenance of the end of the bar26 at a level below the lower edge of stop 3| permits the latching ofstop 3| and bar 26 when bimetal 32 cools suf- 0 flciently. This latchingarrangement cooperates with the return of the actuating means to offposition automatically to prepare the circuit breaker forcircuit-closingoperation. The circuit breaker possesses not only thisadvantage but 5 possesses also the advantage of being trip free." Theelements are so arranged that the circuit breaker cannot be held closedas long as an overload condition exists.

In Fig. 4 a switch without the automatic overload feature is shown. Thecasing of this switch is also preferably made of two sections of moldedinsulating material held together by suitable means. These sections alsohave preformed portions that support the elements of the device withouta positive connection therebetween. A semi-fixed contact support 54 ofslightly different construction is used in the device shown in Fig. 4.This contact support has slots on opposite sides thereof that engageprojections on the sectionsof the casing. The engagement between theslots on the contact support and the projections on the casing guidesthe semi-fixed contact support 54 as it moves during the circuit openingand closing operations. The use of a contact support of this typepermits a somewhat more intimate engagement between the contacts thandoes the use of the semi-fixed contact support 38 shown in Figs. 1, 2,and 3. The contact support 54 moves rectilinearly with the contactcarrier 28 and permits plane contact between the contacts 56 and 44 atall times, The contact support 54 is connected to terminal 40 by aflexible conductor 46. This form of contact support may, of course, beused in the automatic overload breaker shown in the other views. In theswitch shown in Fig. 4, the electro-responsive means is dispensed withand the contact 52 is connected directly to terminal 4| by a flexibleconductor 48. A transverse bar 50 is rigidly connected to the contactcarrier 26 and is bodily movable therewith. On one end of this bar, acam section 25 is formed, and this cam section has a raised portion 2'!thereon, similar to the raised portion shown in Figs. 1, 2, and 3. Thisraised portion 21 on the cam 25 cooperates with the actuating means 26to snap the contact carrier into the "on position. The actuating meansused with the switch is the same actuating means used with the circuitbreaker described above and operates similarly. The switch is operatedby movement of actuating means 20. The actuating means 26 cooperateswith the cam portion. on the bar 52- to provide snap action for thecontact carrier 28 during the circuit making and breaking operation aspreviously described.

Fig. 5 is a perspective view of terminal 40. This terminal has foldedportions that cooperate with formed recesses in the sections of theeasing 22 to support and maintain the terminal in position, Theprojection 60 is formed so that the upstanding portion is wider at theupper end than it is where it joins the terminal. This projection servesto removably secure the terminal 48 to the casing. The projection 58serves not only to prevent movement of the terminal, but serves also asa surface to which flexible conductor 46 is secured. An opening 41 isformed in terminal 40 and is tapped to receive a screw or bolt which maysecure a lead to the terminal.

Fig, 6 is a cross-sectional view of the device shown in Fig. 4 and istaken along the plane 6-6 indicated therein. The view shows in detailthe engagement between terminal 40 and the casing 22. The view alsoshows the dividing plane between the two sections of the casing andshows the manner in which they are secured to each other. A

Fig. 8 is a view of the bottom of the casing and shows the opening 43therein. This opening is designed to permit any gases generated by anare that might form when the circuit is broken, to escape from thecasing. The view also shows the edge of the plane that splits the casing22 into two sections.

Fig. 9 shows an optional form of the invention as applied to a difierenttype of automatic circuit breaker. A plunger 64 has a tripping member 68rigidly attached to it. A catch 66 of springy metal is held at one endby a slot in frame 22 and is free to move at its other end. A transversebar 10 similar to the transverse bar 26 in Figs. 1, 2, and 3 isrotatably attached to contact carrier 28. One end of this bar engagesplunger 64, and the other end engages stop 3| on bimetal 32. The rest ofthe elements are similar to those described in relation to the preferredform of the invention shown in Figs. 1, and 3. The elements of thedevice in Fig. 9 are shown in the on" position,

Fig. 10 shows the elements of this optional form of the invention ingreater detail and shows the elements in the off position after theautomatic circuit-interrupting means has operated to break the circuit.Plunger G4 is shown in one intermediate position along its path oftravel from the "on to oil position. The spring causes further movementof plunger 64 upward and thereby permits the bar 10 to engage the stop3| on the bimetallicelement when the plunger reaches its top position.To close the circuit, the plunger 64 is pressed down. This downwardmovement of the plunger causes a downward movement of the bar 10 whichthe plunger engages, and the contact carrier to which the bar III issecured. When the contact carrier 28 reaches the closed circuitposition, the catch 68 engages one end of the bar 10. The engagementbetween the catch 66 and the end of the bar III holds the contactcarrier in the closed circuit position. To open the circuit, plun er 64is pulled upward.

The upward movement of plunger 64 and the upward movement of thetripping element 68 that is attachedto plunger 64, forces the catch 66to move out of engagement with the bar 10. The bar and the contactcarrier may then move into the open circuit position under the influenceof spring 30. In the event that an overload condition occurs when thecircuit is closed, the electro-responsive means will bend and move outof engagement with the end of bar 10. The elements of the device areshown in Fig. 10 as they appear immediately after the bimetal has movedout of engagement with the bar. The spring 30 thenforces the contactcarrier to move upward and carry the bar with it. A shoulder 14 ismolded in the casing 22 and limits the upward movement of the endof thebar ID. This end of the bar is held at a level below the lower edge ofstop 3| on bimetal 32. Such an arrangement permits the deviceautomatically to prepare itself for circuit-closing operation after anoverload condition,

Figs. 11, 12, and 13 show actuating means 20 and the recess 2| indetail. There is a small raised portion 19 on the periphery of theactuating means 20, and this ridge IS in combination with the recess 2|causes the contact carrier 28 to snap into the ofi position. This snapaction is helpful in preventing the holding of an are between thecontacts 44 and 56.

Fig. 14 shows the semi-fixed contact support 38 and the contact 44 whichit carries. This contact support may be of any suitable material sinceintimacy of engagement between the contacts is not dependent on theresilience of the metal in the contact support. The intimate engagementis secured by the use of a spring positioned beneath the contactsupport. A shield 12 shown inFigs. l5 and 16 is made to slide onto thecontact support 38 to act as a magnetic choke. The efiect of such achoke is the prevention of sudden surges of current through the switch.This tends to limit the intensity of any electrical are that might formwhen the circuit is broken. Figs. 17 and 18 respectively showa side viewand a perspective view of spring 24 which acts to operate actuatingmeans 20.

Figs. 19, 20, and 21 show three views of the reciprocating member 28. Atransverse bar 26 is'"attached pivotally to the member 28 by a pin 23. Aspring 30 is attached to member 28 by a pin 29. The bimetal 32 fits in aslot 33 in member 28 and engages one end of transverse bar 26. Aflexible conductor 34 is connected to bimetal 32 and to terminal 40,Mounted on one end of the bimetal 32 is a stop 3! and mounted on theother end is a contact 56.

Fig. 22 shows the spring which fits under semifixed contact support 38and keeps contact 44 in intimate engagement with contact 55. The use ofa spring of this sort obviates the necessity of using a contact supportof springy metal. This is advantageous because most metals'that havegood resiliency characteristics are not good conductors of electricity.

Fig. 23 shows a battle plate of insulating material 42 which may befitted into slots in the sections of casing 22 and serve to seal thebottom of the circuit maker and breaker. The engagethe invention thatmay be used.

. ambient temperature to trip the device.

'vention. Such a contact support is designed to reduce the likelihood ofholding of an are. It has been found that, when copper gets hot, as inthe case of an overload current condition, it has an afiinity forelectrical arcs. This afiinity draws any arc that might occur betweenthe contacts 44 and 56 to the contact support 16, and

such an arc would burn the contact support. By coating the coppercontact support lit with solder or other lead bearing metals or aninsulating paint, this affinity is curbed and arcing is limited to thesurface of the contact 44. Such an ar rangement lengthens the effectivelife of the contact support.

Fig. 24 shows the member 28 in perspective and shows clearly the shapeof projecting menthere 78 which fit into slides in frame 22 and guidethe member 28.

Fig. 26 is a view of another preferred form of Ihis form is similar tothe preferred form shown in Figs. 1, 2, and 3, and uses the semi-fixedcontact support 38 shown in Fig. 4. Such a contact sup port permits theattainment of an intimate engagement between the contacts and obviatesany bending of the contact support; In addition this form of theinvention shows an electro-re sponsive device of somewhat d'iiierentdesign that might be used. The device is a bimetal i3? that is securedto the contact support 55 on which is mounted contact 56. The bimetall32 is a straight bar that has a catch on the upper end thergof whichengages and holds one end of bar 5.

Figs. 28 and 27 respectively show a plan and elevation view of thecontact support 38 used in the devices shown in Figs. 4 and 25. This contactmay be coated with solder or similar material or a coat ofinsulating paint, and such a coating will serve to confine to thesurface of contact M any arc that might form.

Fig. 29 is a view of another form of spring that may be used to bias theactuating means it to the oif position. This form of spring is some whatless expensive than the form shown in Figs. 1'? and it.

Fig. 30 shows in detail the construction of the bimetal I32. One end ofthe bimetal is secured to the contact support 55 which is carried by thecontact carrier, and the other end is bent to form a catch which engagesone end of the bar 25.

Fig. 31 is a perspective view of the transverse bar 26 that is rotatablysecured to contact carrier 28. The view shows clearly the raised portion21 on the cam portion 25 of the bar. The raised portion 2l cooperateswith the actuating means 20 to snap the contact carrier into the onposition. The view also shows how the cam -portion 25 is widened to givea broader bearing matic circuit breaker of the enclosed type, of

means to compensate for the effect of ambient f temperature. Such ameans is desirable since in many installations, the ambient temperatureis high enough tocause a bending of the bimetal. Where this is true, asmall overload that is less than the rated capacity of the circuitbreaker may add suihcient heat to that given by it ge e means shown inthe drawings'avoids this by providing a catch that movs an amount equalto the movement of the bimetal where suchmovement is caused by ambienttemperature. This means is mounted on and is bodily movable with thecontact carrier. The arrangement of the 5 parts of this compensatingmeans is more clearly shown in Figs. 35 and 36. A novel form oftransverse bar denoted by the numeral illlis provided with a'pin 92 onthe side thereof and a slot 54 inone end thereof. The slot 94 and thepin 92 support a catch 96 whichhas a slot 98 therein that engages pin 92on the transverse bar 9t and a pin that engages the slot 94 in the bar98. The catch 96 also has two pins 99 that engage bimetallic strip M0.The bimetallic strip eon may be designed to have the same thermalcharacteristics as bimetal 32 or bimetal I32 with which it may be used.With such an arrangement, a bending of bimetal 32 or I32 in response toambient temperature will not permit a tripping of the device since thecatch 96 will move with the bimetal 32 or 832 under the influence ofbimetal 500. When an overload condition occurs, bimetal 32 or l32 willbend more than bimetal we since bimetal 32 or 32 has current passingthrough it. By use of this arrangement, a definite current value may berequired to cause a tripping oi the circuit breaker, and this value willnot be aifected by the ambient temperature. Fig. 32 also shows theapplication of an. indicator to a small en- 36 closed type circuitbreaker. The indicator denoted by the numeral W2. has a projection lil lthereon that extends through an opening in the casing of the circuitbreaker 'when the circuit is open as shown in Fig. 32. The indicatori102 has an opening m5 therethrough that engages and is supported by aprojection on the casing. A flat portion on the lower edge of theindicator is arranged to engage and be moved by a cam p0rtion ltd on thetransverse bar Qll. The projec- 459 tlon not is encircled by a spring(ltd which tends to rotate "the indicator so that the projection luddoesnot extend through the opening in the casing of the circuit breaker. Thearrangement of the parts is such that whenever the circuit is closed,the indicator cannot be seen from the outside, but whenever the circuitis open, the projection EM extends through the opening in the casing.The operation of the indicator is so related. to the operation of thevarious parts of the circuit breaker that the indicator will show thatthe circuit is open regardless of the position of the actuating means.Such an indicator is useful where a group of circuit breakers aremounted in a gang and operated by one handle. In such a case, one mightbe tripped and have its actuating means held in the on position by theother breakers. With an indicator of this type, however, it would bepossible to detect I readily the existence of a tripped breaker.

Although the drawings show only a few preferred forms of the invention,it is obvious to those skilled in the art that various changes andalterations may be made in the form of the invention without altering oraffecting its scope.

present invention, switches and automatic circuit breakers of theenclosed type may be made of simple but efilcient construction.

What we claim is:

1. In an electric switch. a semi-fixed contact, a movable contact, amember movable to cause the engagement of the movable contact with thesemi-fixed contact and thereby close the circuit, 7 said movablememberhaving a cam portion It'can be seen, therefore, that by use of thecam portion of the movable member, said sur-- face having a raisedportion thereon, said raised portion on the surface of said actuatingmeans cooperating with the cam portion on said movab1e member toobstruct easy operation of the actuating means to the off position andthus require an added impulse toovercome such obstruction. whereby themovable contact is moved quickly from the closed circuit position to theopen circuit position.

2. In an electric switch, a semi-fixed contact, a movable contact, amember movable to cause the engagement of the movable contact with thesemi-fixed contact and thereby close the circuit, said movable memberhaving a cam portion thereon, a raised portion on said cam portion. anda rotatable actuating mean having a surface in sliding engagement withthe cam por-' tion of the movable member, said raised portion on the camportion of said movable member cooperating with said rotatable actuatingmeans to obstruct easy operation of the rotatable actuating means intothe closed circuit position and thereby require an additional impulse toovercome the obstruction whereby the movable contact is moved quicklyinto contact with the semifixed contact.

3. In an electric switch, a semi-fixed contact,

, semi-fixed contact and thereby close the circuit,

said movable member having a cam portion thereon, a raised portion onsaid cam portion, resilient means tending to disengage the contacts, anda rotatable actuating means having a surface in sliding engagement withthe cam portion of the movable member, said surface having a raisedportion thereon, said raised portion on the cam portion of said movablemember cooperating with the rotatable actuating member to obstruct easyoperation of the actuating means into the closed circuit position andthereby cause rapid closing of the movable and fixed contacts when anadditional impulse i given the actuating means to overcome theobstruction, and said raised portion on the surface of the rotatableactuating means cooperating with the cam portion of said movable memberto obstruct easy operation of the rotatable actuating means to the oposition whereby the additional impulse needed to overcome theobstruction causes a rapid opening of the movable and fixed contacts.

4. In an electric switch, a semi-fixed contact, a movable contact, amember movable to cause the engagement of the movable contact with thesemi-fixed contact and thereby close the circuit, said movable memberhaving a cam' portion thereon, said cam portion having a bearing surfacearea formed thereon that is broader than other portions' of the movablemember, and arotatable actuating means-having a surface in slidingengagement with the broad bearing surface of the cam portion of themovable member.

5. In an electric switch, a casing having formed formed portionstherein, a rectilinearly movable contact, a semi-fixed contact, a membermovable to cause the engagement of the movable contact with thesemi-fixed contact and thereby close the circuit, and resilient meanstending to move the semi-fixed contact toward the movable contact, saidsemi-fixed contact being supported on a flat strip, provided with slotsadapted to oooperate with formed portions in said casing to limitmovement of the semi-fixed contact to a path parallel to the axis oftranslation of the movable contact, said formed portions of the casingbeing arranged to limit the length of travel of the semi-fixed'contact.

6. In an electric switch, a casing having a chamber therein, a coppercontact support positioned in said chamber, a contact mounted on saidcontact support, a second contact movable relative to said coppercontact support, means to cause the engagement of the contacts andthereby close the circuit, and a hardened fluid coating of insulatingmaterial on portions of the copper contact support in the chamber, saidinsulating coating cooperating with the contact mounted on the contactsupport to restrict electrical arcing to the surface of the contact onth contact support.

7. In an electric switch, a semi-fixed contact, a movable contact, amember movable to cause the engagement and disengagement of the movablecontact with the semi-fixed contact and thereby close the circuit, saidmovable member having a cam portion thereon, said cam portion having abroad bearing edge thereon, said broad bearing edge having a raisedportion thereon, and a rotatable actuating means having a surface insliding engagement with the broad bearing edge of the cam portion of themovable member.

8. A circuit breaker comprising a'housing, a contact carrier positionedand guided by the housing for rectilinear movement therein, atransverse. member pivotally secured to the contact carrier, a contactcarried by the contact carrier, a bimetallic element carried by thecontact carrier and electrically connected to the contact at one endthereof, th other end of the bimetallic member engaging one of the endsof the transverse member, a spring biasing the contact carrier to opencircuit position, a rotatable actuating means engaging the other end ofthe pivoted transverse member and arranged to move the transverse memberto operate the contact carrier and close the circuit, a spring biasingsaid actuating means to the open circuit position, said bimetallicelement releasing the contact carrier for movement under influence ofthe biasing spring toward the open circuit position when an excesscurrent flows through the circuit breaker, and means on the housing todepress the end of the transverse member for re-engagement with thebimetallic element when the contact carrier reaches the open circuitposition.

9. A circuit breaker comprising a housing, a contact carrier guided forrectilinear movement in the housing, a contact carried by the contactcarrier relatively movable with respect to said first named contact, atransverse bar pivotally secured to the contact carrier, a conductingbar secured to the contact and extending substantially at right anglesto the contact carrier a distance substantially the same as thetransverse bar extends from the contact carrier, a bimetallic elementsecured to saidconducting bar and engaging one end of the pivotedtransverse bar,

an actuating means actuating the other end of the transverse bar toclose the circuit, said contact carrier being biased to open circuitposition, said bimetallic element arranged to release the transverse barand allow the contact carrier to move to open circuit position underinfluence of the biasing means when an'excess current flows through thecircuit breaker.

10, In an electric switch, a casing having a chamber therein, a coppercontact support positioned in said chamber, a contact mounted on saidcontact support, a second contact movable relative to said coppercontact support, means to cause the engagement of the contacts andthereby close the circuit; and a coating of hardened fluid metal havinglead therein on portions of the copper contact support in the chamber,said coating cooperating with the contact mounted on the contact supportto restrict electrical arcing to the surface of the contact on thecontact support.

ii. In an automatic circuit breaker of the enclosed type, asubstantially stationary contact and a movable contact, said movablecontact being connected to and bodily movable with a contact carrier,two electrothermally responsive devices, a catch engaging one end of oneof the electrotherrnally responsive devices thereby maintaining themovable contact in engagement with the substantially stationary contact,said catch being movable under the influence of the second of theelectrothermally responsive devices, said electrothermally responsivedevices and said catch cooperating to compensate automatically for theeffect of ambient temperature on the automatic circuit breaker.

12. In an automatic circuit breaker of the enclosed type, asubstantially stationary contact and a movable contact, said movablecontact being connected to and bodily movable with a contact carrier,two electrothermally responsive devices, a catch movable with thecontact carrier that is adapted to move relative to the conact carrier,said catch engaging, one end of one of the electrothermally responsivedevices thereby maintaining the movable contact in engagement with thesubstantially stationary contact, said catch being movable relative tothe contact carrier under the influence of the second of theclectrothermally responsive devices, said electrothermally responsivedevices and said catch cooperating to compensate automatically for theeffect of ambient temperature on the automatic circuit breaker.

13. In a circuit breaker, a casing, a'substantially stationary contactsupport biased to closed portion on the broadened face thereof, arotatable actuating means engagingthe cam on the transverse bar, saidrotatable actuating means having a raised portion thereon, an indicatoroperating independently of the rotatable actuating means to indicatewhen the circuit is open, and a pair of electrothermally responsivedevices adapted to compensate automatically for the effect of ambienttemperature on the circuit breaker.

14. In a circuit breaker, a casingga substantially stationary contactsupport biased to closed circuit position by resilient means, a contactsecured to a boss on said contact support, a coating on said contactsupport adapted to restrict any electrical arc to the contact, a movablecontact secured to and -bodily movable with a. contact carrier, saidcontact carrier being guided for rectilinear movement by the casing,said contact carrier having a recess in the bottom thereof to receivethe movable contact, said recess being substantially complementary tothe boss on the substantially stationary contact support and 00-operating with the boss to form a closed chamber around the contacts, atransverse bar rotatably secured to the contact carrier, said transversebar having a cam portion on one end thereof, said cam portion on thetransverse bar'having a raised portion on the broadened face thereof, arotatable actuating means engaging the cam on the transverse bar, saidrotatable actuating means having. a raised portion thereon, anindicator'operating independently of the rotatable actuating means toindicate when the circuit is open, and a pair of electrothermallyresponsive devices adapted to compensate automatically for the effect ofambient temperature on the circuit breaker.

15. In an electric switch, a semi-fixed contact support, a contactsecured to a boss on said contact support, a contact carrier arranged tocarry and support the movable contact, a recess in said contact carrierto receive the movable contact, said recess being substantially thecomplement of the boss on said semi-fixed contact support, and means tomove the contact carrier thereby opening and closing the circuit, saidrecess and said boss cooperating to form a small closed chamber aroundthe contacts in which gases generated when the circuit is broken mayexpand and force the contacts apart.

16. In an electric switch, a semi-fixed contact, a movable contact, amember movable to cause the engagement of the movable contact with thesemi-fixed contact and thereby close the circuit,

said movable member having a cam portion thereon, means biasing thecontacts to the open circuit position, and a rotatable actuating meanshaving a surface in sliding engagement with the cam portion of themovable member, said cam portion and said surface in sliding engagementtherewith being cooperatively configurated to obstruct easy operationthereof immediately ahead of the position whereat the contacts en gageand disengage.

1'2. in an electric switch, a semi-fixed contact, a movable contact, amember movable to cause the engagement of the movable contact with thesemi-fixed contact and thereby close the circuit, said movable memberhaving a cam portion thereon, means biasing the contacts to the opencircuit position, and a rotatable actuating means having a surface insliding engagement with the cam portion of the movable member, said camportion and said surface in sliding engagement therewith beingcooperatively configurated to obstruct easy operation thereofimmediately ahead of the position whereat the contacts ongage to closethe circuit.

18. In an electric switch, a semi-fixed contact, a movable contact, amember movable to cause the engagement of the movable contact with thesemi-fixed contact and thereby close the circuit, said movable memberhaving. a cam portion thereon, means biasing the contacts to the opencircuit position, and a rotatable actuating means having a surface insliding engagement with the cam portion of the movable member, said camportion and said surface in sliding engagement therewith beingcooperatively configurated to obstruct easy operation thereofimmediately ahead of the position whereat the contacts separate to breakthe circuit.

aging the end or the pivoted transverse bar, actuating means arranged toactuate the other end of the transverse bar to close the circuit, meansbiasing the contact carrier to open circuit position, said thermalelement arranged to release the transverse bar and allow the contactcarrier to move to open circuit position under influence of the biasingmeans when an excess current flows through the circuit breaker.

FREDERICK B. ADAM. HENRY M. STIEGLII'Z.

